Ypres - Race leader Vincenzo Nibali and other riders' worst fears came to fruition on Wednesday as heavy rain fell ahead of the start of the fifth stage of the Tour de France.
The 155.5km run from Ypres, Belgium to Arenberg Porte du Hainault includes nine cobbled sections totalling 15.4km.
If those sections aren't tough enough on their own, rain and wind render them even more treacherous.
Nibali, who has been wearing the yellow jersey since winning Sunday's second stage in Sheffield, spoke of the impending doom following Tuesday's stage finish in Lille.
"(Wednesday) it's predicted to rain. We hope it won't because this can complicate everything," he said.
Team Sky's Geraint Thomas also spoke of his worst fears for Wednesday's tricky stage, a tribute to the epic one-day Classic Paris-Roubaix.
"It's going to be a nightmare, no-one's looking forward to it, especially if it rains," said Thomas.
"It's just going to be like riding on ice, especially with some of the corners on the cobbles. It will be last man standing I think."
This stage has had riders and spectators alike excited since the Tour route was announced last September.
But that excitement quickly turned to trepidation for riders as the realisation that it would likely rain dawned on them.
Dutchman Lars Boom expects there to be a shake up in the overall standings at the end of the day.
"We can expect a true show," said the Belkin rider.
"It will be just as nervous as the first three days in Great Britain. The main thing is to hold a good position.
"The several cobblestone sections are far apart from each other, too bad if you ask me, but I think there will still be some time differences at the finish."
The last time the Tour passed through Paris-Roubaix's most notorious territory in 2010 it claimed several victims.
Luxemburger Frank Schleck, brother of Andy who won the Tour that year, broke his collarbone in a crash on the cobbles.
Frenchman Sylvain Chavanel, a Classics specialist, went into the cobbles wearing the yellow jersey but lost it after falling once and suffering two punctures.
To try to minimise the risks, teams use specially designed bicycles just for the cobbles.- Change of bike -
Italian Nibali rode the stage in preparation to discover what was needed.
"More than anything my intention was to find out what material, wheels, etc, I needed to use," said the Astana rider.
"I'm talking about the technical material of the bike, so we'll change the bike."
At Trek, three-time Paris-Roubaix winner Fabian Cancellara played a leading role in designing a bike specifically for the cobbles.
"That bike is a little bit different in that it's longer. In Roubaix you have to go in straight lines and to steer the bike as little as possible, so by making a bike longer it's more stable that way," said Trek mechanic Jordan Ressingh.
"It also has clearance for larger tyres. Typically for a stage we use 22mm or 24mm tyres but for Roubaix we use 27mm tyres.
"In order to use bigger tyres like that we need to have clearance underneath the brakes, so the frame provides that clearance."
At Cannondale they developed a bike that changes the position of the rider to a slightly less aerodynamic one.
"We build in some added features for a little bit more vertical compliance for those rougher days in the saddle," said head of marketing Jonathan Geran.
"To get more comfort we sit the bike a hair more upright.
"That athletic ready position as they're going over cobbles, as they're encountering more bumps in the road that are rougher and that are going to jar them and jar their hands around, that slightly more face up position will keep them more comfortable and keep them more ready."
Above all, the cobbles must be respected and cannot be underestimated.